Provided is an accelerator equipped with a rotary capacitor capable of performing frequency modulation of a high frequency electric field in correspondence with different emission energies for each rotation direction.The accelerator includes an acceleration electrode for accelerating charged particles, an acceleration cavity for supplying electric power to the acceleration electrode to generate a high frequency electric field, and a rotating capacitor for modulating the resonance frequency of the acceleration cavity. The rotating capacitor rotates both in a forward direction and in a reverse direction, and provides temporal variation in electrostatic capacity different at each rotation direction. Frequency modulation is performed by making temporal variations in electrostatic capacitance different at each rotation direction correspond to different emission energies.本發明係提供一種加速器，該加速器係具備有可達成依每一旋轉方向對應不同的出射能量以進行高頻電場之頻率調變的旋轉電容器。加速器係具備：加速電極，係將帶電粒子加速；加速空腔，係將電力供給至加速電極，使高頻電場產生；及旋轉電容器，係使加速空腔的共振頻率調變。旋轉電容器係朝正向及反向之雙向旋轉，取得依每一旋轉方向而不同之靜電電容的時間變化。使依每一旋轉方向而不同之靜電電容的時間變化分別對應不同的出射能量而進行頻率調變。
